Pan type oil burner



Nov. 10, 1953 P. A. BROADY PAN TYPE OIL BURNER Filed Oct. 10, 1950 2 Sheets-Sheet 1 INVENTOR hi um 9 BY WWW ATTORNEY Nov. 10, 1953 P. A. BROADY 2,658,568

PAN TYPE OIL BURNER Filed Oct. 10, 1950 2 Sheets-Sheet 2 INVENTOR Paul Fl. Err-Dad ATTORNEY Patented Nov. 10, 1953 UNITED STATES ATENT OFFICE 2 Claims.

My invention relates to improvements in liquid fuel burners.

An important object of the invention is to provide a pan type oil burner having an open oil pan surrounding a substantially closed vaporizing chamber, and novel air diffusing means for directing the air laterally outwardly in layers above the oil pan and vaporizing chamber.

A further object of the invention is to provide a pan type oil burner which is well adapted to serve as a conversion or replacement unit in existing stoves or furnaces, and which may be manufactured cheaply in sizes to fit substantially any heating requirement.

A further object is to provide a pan type oil burner which is highly simplified in construction, compact and extremely sturdy and durable.

A further object is to provide an oil burner having novel oil feed and vaporizing means which coact with novel combustion air distributing means to form a burner which is highly efiicient, and reliable in operation.

A still further object is to provide an oil burner of the above-mentioned character which is not likely to accumulate heavy carbon deposits upon the vital parts of the burner, and which is very easy to adjust and clean.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this application, and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a central vertical longitudinal section through a liquid fuel burner embodying my invention,

Figure 2 is a horizontal transverse section taken on line 22 of Figure 1, part broken away,

Figure 3 is a similar section taken on line 33 of. Figure 1,

Figure 4 is a similar section taken on line 4-4 of Figure 1,

Figure 5 is an enlarged fragmentary radial section through air diffusing plates, and associated elements,

Figure 5a is a similar section showing a tapered metering screw and associated elements, and,

Figure 6 is a fragmentary radial section through a liquid fuel burner showing separate oil supply lines for the oil pan and vaporizing chamber.

In the drawings, where for'the purpose of illustration are shown preferred embodiments of the invention, attention is directed first to Figures 1 to 5:1 inclusive, wherein the numeral II! designates a cylindrical furnace casing 01' side wall. My

2 burner proper is designated generally by the numeral I2, and the burner is centrally located within the furnace, as shown. A main annular combustion space I I is provided between the furnace side wall It and the periphery of the burner I2.

The burner I2 comprises an outer cylindrical vertical sleeve I3, mounted within the lower end of the casing I0 and preferably substantially contacting the same. The sleeve I3 rests upon a bottom annular horizontal flange I4, rigidly secured to the lower end of the cylindrical casing I0. A lower flat circular plate I5 rests upon the flange I4, and is preferably welded or otherwise rigidly secured to the lower end of the sleeve I3. A narrow annular horizontal plate It is spaced above the lower plate I5, and rigidly secured by welding or the like to the upper end of the sleeve l3. An inner cylindrical vertical sleeve I I has its upper end rigidly secured to the annular plate It, and its lower end rigidly secured to a flat horizontal circular plate I8, concentric with the plate I5 and spaced above the same. The sleeves I3 and I! and the plates I5, I6 and I8 form an annular air jacket or passage I9, which is L-shaped in radial cross section, and arranged adjacent to the lower end of the furnace casing II). The plate I8 and inner sleeve I'i form an annular oil pan inwardly of the air passage I9. The sleeve ii is provided with circumferential rows of air openings 20, and the lowermost row of openings is spaced above the plate [8 a substantial distance.

A large central vertical cylindrical air duct 2| extends through concentric openings 22 and 23 formed in the plates I5 and I8, and the air duct is rigidly anchored in these openings. A lateral branch. duct 24 leads into the vertical duct 2| below the flange I4, and may be connected with a blower or fan, not shown, for creating a forced draft through the burner. The vertical duct 2| is adapted to supply a natural updraft of air to the burner to support combustion, and when a natural draft is used, the blower is not used. The upper end of the duct 2| terminates at the plate I8, and an upwardly flared conical plate or bafiie 25 has its lower end rigidly secured to the upper end of the duct 2| by welding or the like. The upper end of the conical baffle 25 terminates near the elevation of the plate It and is spaced radially inwardly of the sleeve IT, as shown. An annular upwardly tapering pilot burning space is formed between the cylindrical sleeve IT and conical baffie 25, above the plate I8. The upper end of the pilot burning space 26 is somewhat constricted and opens into the main annular combustion space II. The conical baffle 25 is provided with vertically spaced circumferential rows of air c openings 27, preferably arranged at the elevation of the rows of openings 23. The lowermost circumferential row of openings 21 is spaced a substantial distance above the plate [8.

A horizontal annular plate or baffle 28 is rigidly mounted within the upper end of the air duct 2|, at the elevation of the plate 18. This baflle 28 has a circumferential group of openings 29 near its periphery, and a large central opening 30. A relatively short cylindrical depending sleeve 3| has its upper end rigidly secured to the bafile 28, surrounding the central opening 30, and a horizontal perforated plate 32 is rigidly secured to the lower end of the sleeve 3| at an elevation below the plate l5 and slightly above the branch duct 24. The perforated plate 32 serves as an air flow divider, preventing some of the air fiowing upwardly in the duct 2| from entering the sleeve 3! which would otherwise normally do so. The perforations in the plate 32 break up the air entering the sleeve 3! into small streams, which is desirable. Part of the air flowing in the duct 2| passes outside of the sleeve 3i and discharges through the openings 29, as will be more fully described. An inner conical upwardly flared imperforate sleeve 33 has its lower end rigidly secured to the baffle 28 and substantially registering with the opening 39 and upper end of the sleeve 3!. The upper end of the conical sleeve 33 terminates at the elevation of the upper end of the baflle 25. The conical sleeve 33 is concentric with the conical bafile 25 but substantially smaller in diameter than the same, and an annular upwardly flaring air passage 34 is formed between the imperforate sleeve 33 and baffle 25, above the baiiie 28. The air duct 2i is provided near and below the bafile 23 with a circumferential row of air discharge openings 35 leading radially into the annular space i3.

Rigidly secured to the upper ends of the sleeve 33 and baffle 25 is a circular horizontal plate 33 having a large central opening 31 in registration with the upper end of the sleeve 33. The periphery of the plate 35 registers with the upper end of the conical baiiie 25-, and except for the central opening 3'1, the plate 35 is imperforate and completely covers the upper end of the annular air passage 34. Arranged above the plate 36 in vertically spaced superposed concentric relation is a plurality of horizontal circular air diffusing baffles or fins 38, all having the same outside diameters as the plate 33. The fins 33 are provided with central circular openings 39, each of which is successively smaller in diameter than the central opening of the next lowermost fin 38. The central opening 39 of the lowermost fin 38 is only slightly smaller than the opening 31, whereas the openings 39 of the uppermost fins 38 are greatly reduced in diameter with respect to the opening 31.. The arrangement is such that the openings 39 form a central upwardly tapering conical air passage leading from the top end of the sleeve 33. The fins 33 are preferably equidistantly spaced apart vertically, and are maintained spaced by circumferentially spaced sets of small spacer sleeves 49, arranged radially inwardly of the peripheries of the fins 38, as shown. An upper imperforate horizontal cap plate 4| is mounted upon the uppermost spacers 40 and spaced above the uppermost fin 33. This cap plate 43 has the same outside diameter as the fins 38. Upwardly directed vertical bolts 42 extend through the sets of spacer sleeves 43, and through corresponding openings in the fins 33, plate 36 and cap plate 4|. The upper ends of the bolts 42 receive nuts 43, holding the fins and plates together in assembly. The spaced superposed fins 38 form flat horizontal annular air diiiusing passages 44, leading radially outwardly from the upwardly tapering conical air passage formed by the central openings 39.

As best shown in Figure 5, the fins 38 are radially tapered, outwardly of the bolts 42, so that the horizontal annular air diffusing passages 44 are flared or increasing in width near their outer discharge ends, as at 45. The purpose of this construction is to provide an increase in pressure of the air passing radially outwardly in the passages 44, before such air flows into the main combustion space I I, where the temperature and consequently the pressure is increased. Since the pressure of the air discharging from the passages 44 is somewhat increased at 45, this air can force or blast its way into the increased pressure zone of the main combustion space I I and materially aid combustion therein. Likewise the flared construction of the passages 44 at their outer portions 45 prevents backfiring, or the hot gases from entering between the fins 38. The peripheries of the fins 38 are spaced radially inwardly a substantial distance from the furnace side wall In, so that the radial width of the main combustion chamber is substantial, and burning occurs in a continuous annular ring, all about the superposed fins 38. The upper discharge end of the upwardly tapering annular space 26 leads into the main combustion space H at the peripheries of the fins 3B, and due to the upward convergence of the annular passage 23, the velocity of the gases discharging therefrom is considerable.

Rigidly mounted upon the horizontal plate I8, radially outwardly of the vertical duct 2| is a low cylindrical vertical sleeve or wall 46, having its upper end engaging and rigidly secured to the conical baffle 25, below the lowermost openings 27. The wall 46 forms with the conical baffle 25 and plate IS a liquid tight annular fuel vaporizing chamber il which is triangular in radial cross section. Radially inwardly of the wall 46, the plate i8 is provided with circumferentially equidistantly spaced fuel inlet ports 43, preferably four in number, and leading into these ports 48 and having their discharge ends secured to the plate 58 are vertical oil supply lines or tubes 43. The tubes 49 are arranged radially outwardly of the duct 2i, and the tubes are directed radially outwardly at points below the flange 14, as shown at 43'. The tubes lead to a suitable constant level fuel oil metering valve, not shown.

Near and slightly above the horizontal plate 68, the wall 46 is provided with a plurality of circumferentially spaced radial screw-threaded openings 50 which are preferably tapered, and the screw-threaded openings receive adjustable tapered metering screws 51, see Figure 5a. The oil entering the vaporizing chamber 47 through the ports 48 is maintained constantly at the level of the metering screws 5|, and these screws may be adjusted so that some oil will seep through the screw-threaded connections and into the oil pan formed by the plate 18 and sleeve ll. In the oil pan, the oil may rise to the maximum level of the metering screws 5|. Ignition of the burner and pilot burning take place in the oil pan radially outwardly of the wall 4? The wall 46 is provided near the top of the vaporizing chamber ll with a plurality of circumferentially equidistantly spaced radial vapor discharge ports 52, preferably about twelve in number. These ports 52 open into the annular space 26 a substantial distance above the metering screws 51 which limit the maximum oil level in the oil pan.

The operation of my burner is as follows:

Oil from the constant level metering valve, not shown, enters the annular vaporizing cham-- ber 41 from the oil lines 49 and is maintained at the level of the metering screws 51. As previously stated, oil seeps by these screws and builds up to a maximum level of the screws within the oil pan formed by the plate 19 and sleeve l'l. Ignition may be accomplished manually in the oil pan, with a match or the like, or by conventional electrical ignition means, if desired.

Air enters either as a natural updraft from the vertical duct 2| or as a forced draft from the branch duct 24. In either case, the draft is divided at the sleeve 3|, and some air passes upwardly between the sleeve 3| and wall of the duct 2|, to pass through the openings 29 and enter the annular passage 34. From the passage 34, the air discharges through the openings 21, and enters the pilot combustion space 26, where it aids combustion in the oil pan surrounding the vaporizing chamber 41.

Additional air passes upwardly through the perforated plate 32, sleeves 3| and 33, and through the upwardly tapering passage formed by the openings 39. This air is trapped by the cap plate 4|, and strikes the cap plate with a substantial velocity. The trapped air discharges through the horizontal annular passages 44, and travels radially outwardly, and has its pressure increased at 45, prior to entering the main combustion space II. This air enters the main combustion space and aids in supporting combus tion.

The air flow through the burner is constant, and while it is taking place the pilot burning in the oil pan is continuous. The pilot burning heats the fuel oil in the vaporizing chamber 47 until the oil vaporizes and fills the chamber 47 with vapor above the level of the metering screws 5|. Considerable pressure is built up within the annular chamber 41, due to vaporization, and radial jets of vapor are projected through the openings 52 and these jets are ignited by the pilot burning in the oil pan. Air from the opening 20 and 21 comingles with the vapor in the pilot combustion space 26, and the mixed gaseous products ascend rapidly through the constricted upper end of the combustion space 26, where they are further mixed with the radial air blast from the passages 44. The air from the passages 44 forms an annular radially outwardly directed layer moving toward the side wall I!) of the furnace. The main burning takes place within the combustion space H, and this burning is very hot, and combustion of the gaseous products is substantially complete. The main burning in the space H forms a continuous ring of fire about the fins 44. Substantially no carbon is deposited upon the fins 38, since combustion takes place beyond the peripheries of the fins, and the air blast is directed radially outwardly.

In Figure 6, I have shown a slight modification of the invention, wherein a separate oil supply conduit 53 leads to an inlet port 54, formed in the plate [8 radially outwardly of the sleeve 46. In this form of the invention, the metering screws 5| are omitted, and the fuel oil is supplied to the separate conduits 49 and 53 from a dual metering valve of the constant level type, not shown. All other parts are identical with 6 those shown and described in the first form of the invention.

It is to be understood that the forms of the invention, herewith shown and described are to be taken as preferred examples of the same, and that various changes in shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In a liquid fuel burner, an upwardly directed air duct having perforations in its side, a plurality of substantially flat spaced superposed plates arranged near and above the top of the air duct, the uppermost plate being imperforate, the other plates beneath the uppermost plate having central openings to receive the air flowing from the top of the air duct, the air being trapped below the uppermost imperforate plate and discharged radially outwardly in horizontal layers from the spaces between the plates, an oil pan of greater diameter than the air duct and plates surrounding the upper end portion of the air duct and having its top open and disposed adjacent to the top of the air duct, the oil pan having an outer side wall spaced radially outwardly of the peripheries of the plates and air duct, the oil pan and air duct defining an upwardly opening pilot combustion space, a fuel vaporizing ring surrounding the air duct at the bottom of the oil pan and spaced inwardly of the outer side wall of the pan and having radial vapor discharge openings disposed below the perforations of said air duct, and means to supply liquid fuel to the vaporizing ring.

2. In a liquid fuel burner, an upwardly directed air duct having a main opening in its top end, the side wall of the air duct being perforated near and below its top end, air flow divider means mounted within the air duct to direct part of the air to the main opening and part to the perforations of the air duct, a plurality of spaced superposed plates arranged above the top of the air duct and having openings receiving the air flowing from said main opening of the air duct, an imperforate top plate disposed above the up permost superposed plate for trapping air and causing it to spread radially outwardly in layers from the spaces between the superposed plates, a fuel vaporizing ring surrounding the air duct near and below its top end and below the perforations of the air duct and having vapor discharge openings, means to supply liquid fuel to the vaporizing ring, and an oil pan surrounding the air duct and vaporizing ring and having its top open and arranged near the elevation of the top of the air duct and including an outer side wall arranged radially outwardly of the superposed plates, the perforations of the air duct opening into a pilot combustion space defined by the oil pan and air duct.

PAUL A. BROADY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 473,858 Stacey Apr. 26, 1892 1,207,873 DeHlebdon Dec. 12, 1916 1,612,653 Rodriguez Dec. 28, 1926 1,775,458 Henry et al. Sept. 9, 1930 2,263,737 Miller et al Nov. 25, 1941 2,475,947 Clark July 12, 1949 2,480,728 Griewank Aug. 30, 1949 2,483,925 Nagel Oct. 4, 1949 

